Vinyl Liner Feels Like Sandpaper

[mknauss]

R0004 is what I needed to know. That is good for testing pH up to 10 ppm FC. Great.

Your back up chlorine source is cal hypo. You have very low CH. So you can use cal hypo for a long time. You just need to be sure it is fully dissolved after you add it to the pool. Any granules left on your liner can stain it.

When you get Cal Hypo - be sure it does not have the word Blue in the name. That means it has copper in it. You do not want that. If unsure, post a picture of the product you are buying and post here.

Cal hypo should be available at Walmart, Home Depot, Amazon, etc.

 

[geno1005]

Great...thanks for your patience...I'm going on a mission to secure additional chlorine today. Advice...if chlorine is going to be in short supply in our Covid world would the the investment in a SWG system be worth considering? So far we haven't had a worldwide 'run' on salt as far as I know.

 

[mknauss]

Many members have installed SWCG this year. It is always an idea.

I am still concerned with what is on your liner. Did you pour some real acid on it yet? It is only below water line, right?

 

[geno1005]

I still need to put acid directly on the sample. I ran out of daylight before I was able to figure out how to get a tiny amount out of that big bottle and onto something to safe test it. I'll try to solve that mystery today. The whole 'acid' thing makes me nervous to say the least.

The stuff on the liner is present above and below the current waterline. The water was to the very top of the pool from winter precipitation when we removed the cover so the mystery substance is to that original waterline.

I can scratch it off gently with my nails, below and above the current waterline, and now that the chlorine level is higher and the ph level is lower we used a vinyl pool brush just where we could reach under the waterline in one spot and it seemed to come off a tiny little bit easier. After maybe 3 minutes I had pretty much cleared an area 18 inches below the waterline by 3 feet across. It didn't seem to come back overnight.

That said, it didn't 'come right off' by any stretch of the imagination. Hoping it's not something 'unfixable'...maybe it's time to buy a boat instead. I'm very frustrated at this moment...you can't imagine how much I appreciate your advice. Thank you.

 

[mknauss]

Good sign it is being softened by the lower pH or increased FC. You may just have to keep brushing an area at a time and get it off.

It is very odd with your very low CH you have anything that is calcium related.

 

[geno1005]

I finally got back home long enough to test some of the skim off the side of the pool with the acid. We scraped the part above the water line off and placed a small amount of acid on it and yes, it did fizz.

Presumably from the lower ph and higher chlorine, we were able to get most of 'whatever it is' off some of the horizontal surfaces of the liner as far down as we could reach from the top beginning at the 5' part of the pool and pretty much to the pool floor on the 3' end. Originally it would not budge but today it was soft enough that you could take a dish towel and with a bit of pressure could rub most of it off. It took some effort but it was measurably more willing to come off it was at the beginning of the weekend.

In the process of doing that, we also discovered that at least as far as we can tell, there's nothing on the floor or the sloped surfaces of the pool, at least not that we could feel with our feet. It seems to be only on the horizontal surfaces.

As I suspected, the more accurate chlorine test did not arrive today, but our readings this morning were

Chlorine ...somewhere north of 7.5, less than 10
ph...Dropped briefly to 7.0 last night be seems to have stabilized at 7.2
Alkalinity 80
CYA -- 50

The pool water is ever so slightly clearer today. This is the third day that I have elevated the chlorine levels, I'm sure not to SLAM levels, but higher than normal...and we continue to brush it as well.

All suggestions appreciated. Thank you.

 

[mknauss]

Good news on the material fizzing. That makes it calcium scale. The lower pH appears to be releasing it from the surface.

Odd that it formed as your CH is so low. Must have been the perfect condition of elevated pH and cold water.

 

[geno1005]

Glad to know what it is...even more glad to hear that it isn't the worst news it could have been. So are we on the right course of action with the manual rubbing of the surface or is there a better option? I probably got to all but about 15 linear feet of the vertical walls today...between the friction and the chlorine my fingers were literally bleeding by after a few hours and I had to quit for the day.

I estimate that I have 90% of it off 20 to 24 inches from the waterline in all but about those 15 linear feet. My wife stood in the 3' end and was able to reach nearly all the surfaces there all the way down the bottom.

So is the stubborn cloudy water being caused or made worse by the scale condition or is that likely just regular algae?

Thanks again...all your advice is much appreciated!

 

[zea3]

The scale is probably not helping. How often were you dropping pH with the dry acid? Just curious since your scale formation was pretty unique. I'm thinking if you used it fairly often and didn't have much water exchange the sufites built up and you managed to hit perfect conditions to for scale over the winter.
As long as you keep pH lowish 7.0-7.2, and use MA when you need to drop the pH you should be fine going forward.

 

[geno1005]

I had maintained the ph higher than that...probably 7.6 to 7.8 (ish) but when I opened it this year it was higher than I ever remember it, up around 8.2 or 8.4. The water was a different (somewhat brown rather than green) color also...which it had never been before. I had the pool installed in 2004 and I don't recall the water ever being that color before, so I was on a bit of 'high alert' even before I discovered the scale.

I did use the Walmart ph reducer to tackle that the high ph this year, and would have used it last year (and previous years) to lower the ph as needed, I just can't recall how much I might have used it last year...they all start to run together.

So I would be better maintaining the pool closer to 7.2 than 7.6 or 7.8 now that I have it there?

 

[zea3]

I would say yes, although during the summer it may not make as much difference. Definately drop the pH when your close for the season, and maybe figure out a way to check on pH periodically. Does your pool typically freeze over in the winter?
Have you checked CH again since you have been able to get the deposits off the liner?

 

[geno1005]

Yes...the pool freezes at least a couple of times most winters. This past winter was probably one that it was frozen the least that I can remember, both in terms of the number of times and the length each time. I had focused on ph when the pool was open, less when closing, so I will change that for sure.

I haven't checked the CH now that a good portion of the scale is gone...I will do that and let you know.

 

[geno1005]

Here's the update on my pool. The scale that we were able to remove by rubbing last weekend is still gone...the places where we didn't rub it off it's still there. The water is still very cloudy today, exactly 2 weeks after opening the pool. There are little white flakes floating in the water and am finding a collection of something that is likely the same in the water inside the skimmer. It floats on top of the water in the skimmer and is 'slimy' when you stick your finger in it and pull some of it out.

My better test kit, originally supposed to arrive between last Sunday and Tuesday now says it will be here no later than June 1 and as late as June 4, so I've been just keeping the chlorine level on the 'high side' but because I only have the drops and color test I only know in a range how high it is. Frustrating that I ordered the wrong kit, even more frustrating that the replacement is the 'one thing' that Amazon didn't get here when it said. I could have lived without coffee filters the next day.

Chlorine is somewhere around a 10 (pending the better test kit)
CYA is 40
Ph has crept up just a bit from 7.2 last weekend to 7.4 now
Alkalinity is 70

I've continued brushing the pool at least daily and even got frustrated to the point of tossing the Dolphin in the pool one night last week. It looked like it always does when pulling it out, no evidence anything different.

I really don't know what to do next...suggestions welcome. Thank you.

 

[mknauss]

Wait on your kit. The slimy stuff floating is dead algae or something organic. Chlorine will take care of it.

 

[geno1005]

Thanks...this thing is trying my patience to be sure. I just retested the calcium in the water...and if I'm doing the test right, it's still right at 50. If I'm spinning that little wheel that comes with the kit correctly, that appears to be well in the acceptable range for my ph and alkalinity? Am I doing that correctly?

 

[mknauss]

Honestly I do not know anything about that wheel. We at TFP use CSI. Poolmath calculates it based on your test data. Keeping it on the negative side for you would be good with your deposits on the liner.

 

[33feet]

Just wanted to let you know Geno1005 that you are not the only having this issue. I am also, very similar circumstances. Won't hijack your thread, just wanted to let you know , you are not the only one this year with side wall grit. Maybe it's a Midwest thing....

 

[geno1005]

Well...we are off on the SLAM! My more accurate kit arrived yesterday and last night I boosted the chlorine level in the pool to 10. I also brushed the pool yesterday and put the dolphin in the pool last night for about 90 minutes.

This morning the water looks the same (cloudy, lose sight of the dolphin at about 4 feet, pool is completely blue however), and for the first time that I can ever remember, I couldn't see any movement in skimmer whatsoever. I had just backwashed the filter yesterday morning so that became pretty much jammed, it seems, in 24 hours.

Anyway, the chlorine levels this morning had fallen back to an 8 so I added the 50 ounces of 10% solution that the pool calculator recommends.

Everything else (perhaps with the exception of calcium) seems well within the acceptable ranges:

Chlorine 8 (was 10 last night at 9, added 10% solution at 7am)
Combined Chlorine 0.5
Ph 7.2
Alkalinity 70
Calcium Hardness 50
CYA 40

So is clogging of the filter a cause for alarm, or does that just mean it's doing what it's supposed to do? I noticed that 'backwashing frequently' was in the instructions.

Thanks for the advice. Much appreciated.

 

[zea3]

Your filter is clogging because it is doing its job and collecting debris (aka dead algae). Clean the filter when you see a 20% rise from clean pressure. Once clean flow should be restored until the filter needs another cleaning. How often that will happen depends on the type and size of filter and the debris load in the water. If cleaning doesn't restore flow report the issue and we can troubleshoot from there.

 

[mknauss]

Gene -- read the SLAM Process again. Your FC needs to be kept at SLAM level FC as often as possible each day. With a CYA of 40, your SLAM level FC is 16 ppm. So raise your FC to that level and test and add chlorine several times per day to that level.

What filter do you have? Can you add that to your signature?